Erle Stanley Gardner was born in Malden, Massachusetts. His father, a mining engineer, took the family to Portland, Oregon, and then to the small mining town of Oroville. During these years Gardner picked up a knowledge of mining, which was later reflected in his novels. In 1909 he graduted from Palo Alto High School in the San Francisco Bay Area.

As a young man Gardner led a somewhat unconventional life. He was kicked out of Valparaiso University in Indiana after only a few weeks, ostensibly because he was involved in a fistfight. Later he boxed and arranged unlicensed wrestling matches. While working as a typist in a law office in California, he "read law" — and without any formal legal education — passed the bar in 1911. At the age of 21 he opened his own law office in Merced, California, but his practice was not successful.

From 1911 to 1918, he worked as a lawyer for a corporate attorney in Oxnard, California. In 1921 he married Natalie Frances Talbert, and they had one child. From Oxnard he moved to Ventura, where he was a partner in a law firm. In the early 1920s he began writing for the pulp magazines and was a very successful pulp writer of mysteries, westerns, and science fiction before he published his first novel.

His science fiction stories included "Rain Magic" (1928), "Monkey Eyes" (1929), "The Sky's the Limit" (1929), "A Year in a Day" (1930), "The Man with Pin-Point Eyes" (1931), "The Human Zero" (1931), and "New Worlds" (1932) — all published in Argosy Magazine. "The Human Zero," "New Worlds," and "Rain Magic" were reprinted in the SF magazine Fantastic in the early 1960s. A collection of all the stories published in Argosy, The Human Zero: The Science Fiction Stories of Erle Stanley Gardner, edited by Martin H. Greenberg and Charles G. Waugh, was published in 1981. Most critics consider these to be all of Gardner's SF/fantasy stories, but he also wrote other stories with fantastic elements. In addition, he wrote stories about such fantastic characters as El Paisano (who could see in the dark), Reed Sample (a psychic), and Speed Dash (a human fly with a photographic memory and almost superhuman abilities).

Gardner's own account of his days writing about such characters in the pulp magazines, "Speed Dash," was published in the June, 1965, issue of The Atlantic Monthly.

Gardner's mysteries were extremely popular, and led to radio programs, television shows, and movies. His genre stories, on the other hand, have been largely ignored. Martin H. Greenberg and Charles G. Waugh, compilers of The Human Zero collection, however, were quite complimentary and stated that "Gardner possessed many of the characteristics of the typical science fiction fan: a feeling of not fitting in as an adolescent, an avid curiosity, a high intelligence, a great propensity for and enjoyment of arguing with people, and a tendency to alternate periods of solitude with periods of multiple companionship."